That was me.  It's been a couple of years and I don't remember the value
resistor I ended up with.  After I got the LED physically mounted I
experimented with different value resistors in a dark garage so that the
brightness was similar to that of the other dash lights and varied somewhat
with the control at the headlight switch.
   I believe that the value was in the vicinity of 1000 ohms.  If you put
things together temporarily and bring the wires out with clip leads you can
try various values.  1/4 W resistors would be fine.   If you put a current
meter in the circuit you can check that you are staying a little below the
max current rating for the LED.  15 or 20 mA is common.

Larry A.

On Wed, Oct 15, 2008 at 12:42 PM, Allan Streib <streib@cs.indiana.edu>wrote:

> I need replacement lamps for the heat/vent controls.  In a black plastic
> carrier with small spade connectors.  The little twist-lock lamps for
> the instrument panel are easy to find, but I have not found anyone who
> sells these larger ones.  Is this a matter of carefully replacing the
> bulb itself?  A dealer item?
>
> Someone mentioned that they replaced theirs with LEDs, do you have any
> specifics on resistance needed etc?
>
> Thanks,
>
> Allan
> --
> 1991 Vanagon GL
>